/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    FirstOrder.java
 *    Copyright (C) 1999-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Vector;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.DenseInstance;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Range;
import weka.core.SparseInstance;
import weka.core.UnsupportedAttributeTypeException;
import weka.core.Utils;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.StreamableFilter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> This instance filter takes a range of N numeric
 * attributes and replaces them with N-1 numeric attributes, the values of which
 * are the difference between consecutive attribute values from the original
 * instance. eg: <br/>
 * <br/>
 * Original attribute values<br/>
 * <br/>
 * 0.1, 0.2, 0.3, 0.1, 0.3<br/>
 * <br/>
 * New attribute values<br/>
 * <br/>
 * 0.1, 0.1, -0.2, 0.2<br/>
 * <br/>
 * The range of attributes used is taken in numeric order. That is, a range spec
 * of 7-11,3-5 will use the attribute ordering 3,4,5,7,8,9,10,11 for the
 * differences, NOT 7,8,9,10,11,3,4,5.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -R &lt;index1,index2-index4,...&gt;
 *  Specify list of columns to take the differences between.
 *  First and last are valid indexes.
 *  (default none)
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Len Trigg (trigg@cs.waikato.ac.nz)
 * @version $Revision$
 */
public class FirstOrder extends Filter implements UnsupervisedFilter, StreamableFilter, OptionHandler, WeightedInstancesHandler {

    /** for serialization */
    static final long serialVersionUID = -7500464545400454179L;

    /** Stores which columns to take differences between */
    protected Range m_DeltaCols = new Range();

    /**
     * Returns a string describing this filter
     * 
     * @return a description of the filter suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {

        return "This instance filter takes a range of N numeric attributes and replaces " + "them with N-1 numeric attributes, the values of which are the difference " + "between consecutive attribute values from the original instance. eg: \n\n" + "Original attribute values\n\n" + "   0.1, 0.2, 0.3, 0.1, 0.3\n\n" + "New attribute values\n\n" + "   0.1, 0.1, -0.2, 0.2\n\n" + "The range of attributes used is taken in numeric order. That is, a range " + "spec of 7-11,3-5 will use the attribute ordering 3,4,5,7,8,9,10,11 for the " + "differences, NOT 7,8,9,10,11,3,4,5.";
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> newVector = new Vector<Option>(1);

        newVector.addElement(new Option("\tSpecify list of columns to take the differences between.\n" + "\tFirst and last are valid indexes.\n" + "\t(default none)", "R", 1, "-R <index1,index2-index4,...>"));

        return newVector.elements();
    }

    /**
     * Parses a given list of options.
     * <p/>
     * 
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -R &lt;index1,index2-index4,...&gt;
     *  Specify list of columns to take the differences between.
     *  First and last are valid indexes.
     *  (default none)
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the list of options as an array of strings
     * @throws Exception if an option is not supported
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        String deltaList = Utils.getOption('R', options);
        if (deltaList.length() != 0) {
            setAttributeIndices(deltaList);
        } else {
            setAttributeIndices("");
        }

        if (getInputFormat() != null) {
            setInputFormat(getInputFormat());
        }

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Gets the current settings of the filter.
     * 
     * @return an array of strings suitable for passing to setOptions
     */
    @Override
    public String[] getOptions() {

        Vector<String> options = new Vector<String>();

        if (!getAttributeIndices().equals("")) {
            options.add("-R");
            options.add(getAttributeIndices());
        }

        return options.toArray(new String[0]);
    }

    /**
     * Returns the Capabilities of this filter.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Sets the format of the input instances.
     * 
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws UnsupportedAttributeTypeException if any of the selected attributes
     *                                           are not numeric
     * @throws Exception                         if only one attribute has been
     *                                           selected.
     */
    @Override
    public boolean setInputFormat(Instances instanceInfo) throws Exception {

        super.setInputFormat(instanceInfo);

        m_DeltaCols.setUpper(getInputFormat().numAttributes() - 1);
        int selectedCount = 0;
        for (int i = getInputFormat().numAttributes() - 1; i >= 0; i--) {
            if (m_DeltaCols.isInRange(i)) {
                selectedCount++;
                if (!getInputFormat().attribute(i).isNumeric()) {
                    throw new UnsupportedAttributeTypeException("Selected attributes must be all numeric");
                }
            }
        }
        if (selectedCount == 1) {
            throw new Exception("Cannot select only one attribute.");
        }

        // Create the output buffer
        ArrayList<Attribute> newAtts = new ArrayList<Attribute>();
        boolean inRange = false;
        String foName = null;
        int clsIndex = -1;
        for (int i = 0; i < instanceInfo.numAttributes(); i++) {
            if (m_DeltaCols.isInRange(i) && (i != instanceInfo.classIndex())) {
                if (inRange) {
                    Attribute newAttrib = new Attribute(foName);
                    newAtts.add(newAttrib);
                }
                foName = instanceInfo.attribute(i).name();
                foName = "'FO " + foName.replace('\'', ' ').trim() + '\'';
                inRange = true;
            } else {
                newAtts.add((Attribute) instanceInfo.attribute(i).copy());
                if ((i == instanceInfo.classIndex())) {
                    clsIndex = newAtts.size() - 1;
                }
            }
        }
        Instances data = new Instances(instanceInfo.relationName(), newAtts, 0);
        data.setClassIndex(clsIndex);
        setOutputFormat(data);
        return true;
    }

    /**
     * Input an instance for filtering. Ordinarily the instance is processed and
     * made available for output immediately. Some filters require all instances be
     * read before producing output.
     * 
     * @param instance the input instance
     * @return true if the filtered instance may now be collected with output().
     * @throws IllegalStateException if no input format has been defined.
     */
    @Override
    public boolean input(Instance instance) {

        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }
        if (m_NewBatch) {
            resetQueue();
            m_NewBatch = false;
        }

        Instances outputFormat = outputFormatPeek();
        double[] vals = new double[outputFormat.numAttributes()];
        boolean inRange = false;
        double lastVal = Utils.missingValue();
        int i, j;
        for (i = 0, j = 0; j < outputFormat.numAttributes(); i++) {
            if (m_DeltaCols.isInRange(i) && (i != instance.classIndex())) {
                if (inRange) {
                    if (Utils.isMissingValue(lastVal) || instance.isMissing(i)) {
                        vals[j++] = Utils.missingValue();
                    } else {
                        vals[j++] = instance.value(i) - lastVal;
                    }
                } else {
                    inRange = true;
                }
                lastVal = instance.value(i);
            } else {
                vals[j++] = instance.value(i);
            }
        }

        Instance inst = null;
        if (instance instanceof SparseInstance) {
            inst = new SparseInstance(instance.weight(), vals);
        } else {
            inst = new DenseInstance(instance.weight(), vals);
        }

        copyValues(inst, false, instance.dataset(), outputFormatPeek());

        push(inst); // No need to copy instance
        return true;
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String attributeIndicesTipText() {
        return "Specify range of attributes to act on." + " This is a comma separated list of attribute indices, with" + " \"first\" and \"last\" valid values. Specify an inclusive" + " range with \"-\". E.g: \"first-3,5,6-10,last\".";
    }

    /**
     * Get the current range selection
     * 
     * @return a string containing a comma separated list of ranges
     */
    public String getAttributeIndices() {

        return m_DeltaCols.getRanges();
    }

    /**
     * Set which attributes are to be deleted (or kept if invert is true)
     * 
     * @param rangeList a string representing the list of attributes. Since the
     *                  string will typically come from a user, attributes are
     *                  indexed from 1. <br>
     *                  eg: first-3,5,6-last
     * @throws Exception if an invalid range list is supplied
     */
    public void setAttributeIndices(String rangeList) throws Exception {

        m_DeltaCols.setRanges(rangeList);
    }

    /**
     * Set which attributes are to be deleted (or kept if invert is true)
     * 
     * @param attributes an array containing indexes of attributes to select. Since
     *                   the array will typically come from a program, attributes
     *                   are indexed from 0.
     * @throws Exception if an invalid set of ranges is supplied
     */
    public void setAttributeIndicesArray(int[] attributes) throws Exception {

        setAttributeIndices(Range.indicesToRangeList(attributes));
    }

    /**
     * Main method for testing this class.
     * 
     * @param argv should contain arguments to the filter: use -h for help
     */
    public static void main(String[] argv) {
        runFilter(new FirstOrder(), argv);
    }
}
